1. Field
One or more embodiments of the present invention relate to rechargeable secondary batteries.
2. Description of the Related Art
According to technology developments and increases in production of mobile devices such as mobile phones and laptop computers, demand for secondary batteries as an energy source is rapidly increasing. Recently, as an alternative energy source to fossil fuels, research into secondary batteries for use in electric vehicles or hybrid vehicles is actively conducted.
However, an external impact such as a dropping impact during impact resistance tests such as drop tests and oscillation tests or during distribution or use of products may cause an inner short circuit in secondary batteries.